Techniques of indicating data available in an uplink data buffer of a communication device (UE) to a cellular network are known. E.g., from the Third Generation Partnership Project (3GPP) Technical Specification (TS) 36.321, version 12.2.1 of Jun. 10, 2014, it is known to send a buffer status report (BSR) including the buffer size field which identifies the total amount of data available in the uplink data buffer of the UE. The indication of the data available in the uplink data buffer may be employed by a network node of the cellular network to allocate further uplink radio resources to the UE. The UE can then perform uplink transmission of the data in the uplink data buffer by employing the further uplink radio resources.
However, such techniques face certain restrictions. In particular, scenarios are known where—prior to the sending of the BSR—uplink radio resources had been previously allocated to the UE for uplink transmission in reoccurring time intervals. The UE may employ these previously allocated uplink radio resources for the uplink transmission of at least parts of the data in the uplink data buffer. Then a mismatch between the further radio resources allocated to the UE based on the BSR and the actually required radio resources may occur. This may lead to inefficiencies when allocating the further uplink radio resources on the uplink data channel.